Occurrence and concentration of mycotoxins in maize dried distillers' grains produced in Brazil

The presence of mycotoxins in dried distillers' grains with solubles (DDGS), a by-product of bioethanol production from maize, has been a matter of concern due to the increasing global utilisation of this ingredient in animal feed. In this study, 186 samples of maize DDGS produced in Brazil were analysed for the presence of major mycotoxins: aflatoxins (B-1, B-2, G(1), and G(2)), fumonisins (B-1 and B-2), zearalenone (ZEN), deoxynivalenol (DON) and ochratoxin A (OTA). Samples were provided by the local industry between January 2017 and October 2020, and mycotoxins were quantified by LC-MS/MS. More than 98% of the analysed samples were contaminated with mycotoxins, from which 59.9% had a single mycotoxin, 29.9% two mycotoxins, and 9.1% more than two mycotoxins. The most prevalent metabolites were fumonisin B-1 and B-2, being detected in 98.8% (mean 3,207 mu g/kg) and 97.6% (mean 1,243 mu g/kg) of the samples, respectively; aflatoxin B-1 had the third highest positivity, with 32.3% (mean 1.47 mu g/kg), followed by ZEN, with 18.01% (mean 18.2 mu g/kg), DON, with 12.9% (mean 59.6 mu g/kg), and OTA was not detected. Co-occurrence of total aflatoxins (AFT = aflatoxin B-1+B-2+G(1)+G(2)) and total fumonisins (FBT = fumonisin B-1+B-2) was observed in 32.07% of the samples analysed for these mycotoxins. Co-occurrence of AFT and ZEN was found in 7.84% of the samples analysed for such mycotoxins, while FBT and DON co-occurred at 13.01%. AFT, FBT, DON and ZEN co-occurred in only one sample (0.84%). Except for FBT, a considerable number of samples presented the evaluated mycotoxins below their respective limit of quantification (LOQ) with percentages of 67.61% for AFT, 81.99% for ZEN, 87.07% for DON and 100% for OTA. Since the production of bioethanol and its by-products is growing worldwide, including in Brazil, mycotoxicological monitoring of maize DDGS is crucial to identify the effects of mycotoxins occurrence in animal feed formulated with this ingredient.